import { Editor } from '../../editor/Editor.js';
import { ContextMenuDirectory, ContextMenuReadOnlyEntry } from '../context-menu/context-menu.js';

declare const CodeMirror: any;

class CodePanel extends HTMLElement
{
  currentPath: string | null = null;
  _pinned: boolean = false;
  _cm: any = null;
  _initialized = false;
  _ignoreChange = false;

  connectedCallback(): void
  {
    if ( this._initialized ) return;
    this._initialized = true;

    this.className = 'code-panel';
    this.innerHTML = `
      <div class="cp-toolbar">
        <button class="cp-pin" title="Pin — keep this file when selecting others">Pin</button>
        <button class="cp-undo" title="Undo (Ctrl+Z)" disabled>↩</button>
        <button class="cp-redo" title="Redo (Ctrl+Y)" disabled>↪</button>
        <button class="cp-save" title="Save (Ctrl+S)" disabled>Save</button>
      </div>
      <div class="cp-empty">Open a file from the file tree</div>
      <div class="cp-editor" style="display:none"></div>
    `;

    const editorDiv = this.querySelector( '.cp-editor' ) as HTMLElement;

    this._cm = CodeMirror( editorDiv,
    {
      value: '',
      lineNumbers: true,
      theme: 'cp-dark',
      indentWithTabs: false,
      tabSize: 2,
      indentUnit: 2,
      lineWrapping: false,
      readOnly: false,
    } );

    this._cm.on( 'change', () => this._onContentChanged() );

    this.querySelector( '.cp-pin' )!.addEventListener( 'click', () => this._togglePin() );
    this.querySelector( '.cp-save' )!.addEventListener( 'click', () => this._save() );
    this.querySelector( '.cp-undo' )!.addEventListener( 'click', () => this._cm.undo() );
    this.querySelector( '.cp-redo' )!.addEventListener( 'click', () => this._cm.redo() );

    Editor.get().onDocumentOpened.addListener( ( e ) =>
    {
      if ( 'code-panel' !== e.editorTag ) return;
      if ( e.targetElement && e.targetElement !== this ) return;
      if ( ! this._pinned ) this._loadDocument( e.path, e.content );
    } );

    document.addEventListener( 'keydown', ( e: KeyboardEvent ) =>
    {
      if ( ! this.currentPath ) return;
      if ( e.ctrlKey && e.key === 's' ) { e.preventDefault(); this._save(); }
    } );
  }

  _loadDocument( path: string, content: string ): void
  {
    this.currentPath = path;
    this._updateTabLabel( path );

    this.querySelector( '.cp-empty' )!.setAttribute( 'style', 'display:none' );
    ( this.querySelector( '.cp-editor' ) as HTMLElement ).style.display = '';

    this._ignoreChange = true;
    this._cm.setValue( content );
    this._cm.clearHistory();
    this._cm.setOption( 'mode', this._resolveMode( path ) );
    this._ignoreChange = false;

    this._updateButtons( false );
    this._cm.refresh();
  }

  _resolveMode( filePath: string ): string
  {
    const name = filePath.slice( filePath.lastIndexOf( '/' ) + 1 );

    if ( name.endsWith( '.js' ) || name.endsWith( '.json' ) ) return 'javascript';
    if ( name.endsWith( '.ts' ) ) return 'javascript';
    if ( name.endsWith( '.css' ) ) return 'css';
    if ( name.endsWith( '.html' ) || name.endsWith( '.htm' ) ) return 'htmlmixed';
    if ( name.endsWith( '.xml' ) || name.endsWith( '.svg' ) ) return 'xml';
    if ( name.endsWith( '.md' ) ) return 'markdown';

    return 'null';
  }

  _onContentChanged(): void
  {
    if ( this._ignoreChange || ! this.currentPath ) return;

    const content = this._cm.getValue();
    Editor.get().markDirty( this.currentPath, content );
    this._updateButtons( true );
  }

  _togglePin(): void
  {
    this._pinned = ! this._pinned;
    this.querySelector( '.cp-pin' )!.classList.toggle( 'pinned', this._pinned );
  }

  async _save(): Promise<void>
  {
    if ( ! this.currentPath ) return;
    await Editor.get().save( this.currentPath );
    this._updateButtons( false );
  }

  _updateTabLabel( path: string ): void
  {
    const name = path ? path.slice( path.lastIndexOf( '/' ) + 1 ) : '';
    this.dispatchEvent( new CustomEvent( 'panel:label-change', { bubbles: true, detail: { label: '📝 ' + name } } ) );
  }

  _updateButtons( dirty: boolean ): void
  {
    ( this.querySelector( '.cp-save' ) as HTMLButtonElement ).disabled = ! dirty;
    ( this.querySelector( '.cp-undo' ) as HTMLButtonElement ).disabled = this._cm.historySize().undo < 1;
    ( this.querySelector( '.cp-redo' ) as HTMLButtonElement ).disabled = this._cm.historySize().redo < 1;
  }

  addContextMenuEntries( dir: ContextMenuDirectory ): void
  {
    if ( this.currentPath )
    {
      dir.add( new ContextMenuReadOnlyEntry( dir, `Editing: ${this.currentPath}` ) );
    }
    else
    {
      dir.add( new ContextMenuReadOnlyEntry( dir, 'No file open' ) );
    }
  }
}

customElements.define( 'code-panel', CodePanel );